InsiderTrades

Form 4 for MASS 908 Devices Inc.

Accepted 2026-05-04 16:30:16 ET · period of report 2026-05-01 · accession 0001836876-26-000007 · SEC index · Original document

Summary rows

Aggregated the way they appear in lists: one row per insider, transaction code and security table.

X Filed Traded Ticker Insider Title Type Price Qty Owned ΔOwn Value
D 2026-05-04 16:30 2026-05-01 MASS Kenneweg John SVP, Sales, Product Marketing M - OptEx — +26.0K 83.8K +45% —
D 2026-05-04 16:30 2026-05-01 MASS Kenneweg John SVP, Sales, Product Marketing S - Sale+OE $6.83 -7,787 76.0K -9% -$53.2K
D 2026-05-04 16:30 2026-05-01 MASS Kenneweg John SVP, Sales, Product Marketing M - OptEx $0.00 -26.0K 0 -100% $0

Purchase Sale Sale after option exercise All abbreviations

Every reported transaction

#TableSecurityDateCodeA/DSharesPriceOwned afterOwnExercise / expiryUnderlyingFootnotes
1 Common Common Stock 2026-05-01 M A 26,042 — 83,826 D — — (F1) Each performance stock unit ("PSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested.
2 Common Common Stock 2026-05-01 S D 7,787 $6.83 76,039 D — — (F2) The sale reported on this Form 4 represents shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting and settlement of PSUs. The sale is mandated by the Issuer's election to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary transaction by the Reporting Person.
3 Derivative Performance Stock Units 2026-05-01 M D 26,042 $0.00 0 D — · — to — 26,042 Common Stock (F1) Each performance stock unit ("PSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested. (F3) The PSUs vested, in accordance with their terms, on May 1, 2026. The PSUs had no expiration date. (F3) The PSUs vested, in accordance with their terms, on May 1, 2026. The PSUs had no expiration date.